Process of reducing metallic oxids.



C. A. PFANSTIEHL.

PROCESS 0F REDUCING MALLIC OXIDS.

Armenio" mw nov. ls, me.

1,283,286. Patented Oct. 29, 1918.

l Highland Park, in

CARL A. PFANSTIEHL, 0F HIGHLAND COMPANY, INC., OF NORTH CHICAGO,

PARK,

ILLINOIS, A CORPORATION OF NEW YORK.

ILLINOIS, ASSIG'NOB TO PFANSTIEHL PROCESS OF BEDUCING METALLIC OXIDS.

Original application filed October 15, 1915,

To all whom it may concern.'

Be it known that I, CARL A. PFANsTmHL, a a citizen of the United States,residing at the county of Lake and State of Illinois, have invented acertain new and useful Improvement in the Processes of Reducing MetallicOxids, of which the following is a full, clear, concise, and exactdescription, reference being had to the accompanying drawings, forming apart of this specification.

My invention relates to the process of reducing metallic oxids andparticularly to a process which insures the rapid and complete reductionof the material with practically no reoxidization by the condensation ofmoisture created by the reduction process.

In order to produce malleable tungsten with little or no mechanicalworking of the metal after it has been fused into an ingot, it has vbeenfound to be important that the tungsten powder from which theI tungsteningots are formed be very fine and absolutely free from tungsten trioxidfrom which it is ordinarily formed. d

In a co-pending application 872,952 I have described a process for theproduction of tungsten trioxid in a very finely divided state and fromwhich powdered tungsten satisfactory for the production of malleabletungsten may be secured. The present invention relates to a process forreducing the tungsten trioxid to tungsten powder in a manner whichexperience has shown produces very fine and pure tungsten powder.

This application is a division of my copending a plication Serial No.55,942, filed October 1 1915, relating to the apparatus by which theherein described process may be readily carriedout.

It has ybeen found important that the hydrogen gas brought into contactwith the tungsten trioxid for .reducing purposes be kept circulatingover the surface of the tungsten trioxid at a high velocity so that thegas will become only slightly laden with water vapor given o during thereducing process. It has also been found that if the hydrogen gas isbrought into contact with the heated tungsten trioxid at a temperaturesubstantially equal to the temperaturel of the trioxid and that ifduring the passage of the hydrogen over the tungsten trioxid the sametemperature is maintained none of the water Specification of LettersPatent.

with magnesia, or

Patented oct. 29, 191s.

Serial No. 55,942. Divided and this application led November Serial No.131,633.

moving hyvapor picked up by the rapidl in the tungdrogen will be againdeposite sten.

Apparatus satisfactory for carrying out this process is illustrated inthe accompanying drawings in which- Figure 1 is an elevation of thefurnace in which the external electrical connections arediagrammatically illustrated;

Fig. 2 is a section through Fig. 1 on a somewhat larger scale and with aportion of the refractory tube broken away, and

Fig. 3 is a perspective of in which the tungsten trioxid is supported soas to be exposed to the passing hydrogen gas.

The preferred form of apparatus for carrying out my invention hereinillustrated comprises a main tube 5 of refractory material, such assilica or porcelain, this tube being in the commercial device about livefeet long and two and one-half inches in diameter. Surrounding a portionof t e tube 45 is a second metal tube 6, of larger diameter, the spacebetween the two tubes being packed other refractory sand as indicated at7. Encircling the tube 5 an in contact therewith throughoutsubstantially two-thirds of the portion thereof inclosed by the tube 6is a heating coil 8 of nickel-chromium or other non-oxidizing resistancewire. The left end of the refractory tube 5 extends several inchesbeyond the end of the tube 6 and carries the metallic water jacket 10having an opening therein of substantially the same bore as that of thetube 5. Into the outer end of this bore is fitted a stopper 12 throughwhich a hydrogen intake tube 13 passes and through which also passconducting bars 14 upon the inner ends of which the hydrogen heatingnichrome coil 16 is supported, this coil being adapted to be withdrawnfrom the end of the tube with the removal of the stopper 12. Theexternal ends of the conducting bars 14 are connected into a suitableelectric circuit, as diagrammatically shown in Fig. 1. The tube 5extends for a distance of substantially two feet beyond the right end ofthe inclosing tube 6 and is not throughout this space provided witheither heating or cooling means. The extreme right end of the tube 5,however, is provided with a metallic water jacket 18 similar inconstruction to the water jacket the. nest of trays 10 at the left endof the tube 5, with the exception that the jacket 18 is provided withmore extensive cooling surfaces. A sto per 20 is provided for theexposed end o the jacket 18 and through this the hydrogen exhaust tube21 and the water drain 22 extend, the drain'22 being connected with areservoir 2B intoL which the'water :formed by the chemical union of thereleased oxygenaaid the hydrogen collects, this water being condensed bythe contact of the vapor with the coolA watenacketed member 18.

Fig` 3 il ustrates the'bcat 25 carrying a nest of trays 26 and 27 inwhich the tungsten trioxid is distributed for the reducing operation.These trays and the boat carrying them are preferably constructed of urenickel, the boat being provided with nickel crossrods 28 for supportingthe trays one above the other so that space is provided for thecirculation of the hydrogen gas between the top of the tungsten trioxidand the base of the tray next above. Tungsten trioxid is also placedfinthe lower part of the boat 25 to a height somewhat less than the levelof the base of the lower tray.

In operating my reducing furnace, the boat 25 and its accompanying traysare filled to the proper level with vtungsten trioxid and the stopper 12having been removed and the nic el or tungsten wire 30 havin beenattached to the boat 25 and thrcaed through the hydrogen exhaust 21, theboat with its Acontents is drawn into the position shown in Fig. 2. Thestopper 12 is then replaced and both electric circuits are completed andthe supply of hydrogen gas turned into the tube 13. The heating coils 16and 8 gradually bring the'temperature of the tube and the hydro encontained therein u to that degree at w ich hydrogen attacks e tungstentrioxid, reducing it to pure tungsten. The hydrogen gas 1s kept 1n rapidcirculation across the surface of the tungsten trioxid until all of thetrioxid has been reduced to pure tun sten. During this operation a parto the water produced by the chemical union of the reeased oxy en and thehydrogen passes out throug the tube 21 in the form of vapor, while thereater part thereof 1s condensed and con ucted into the reservoir-naturally drain to the right end of the furnace. After the reducingoperation is continued for that length of time necessary for com letereduction of the tungsten trioxid, the oat with its contents is drawninto that portion of the tube' which is not surrounded by theheat-retaining material 7 and tube 6 and is there allowed to stand untilits tem rature is reduced suiciently that it may e exposed to the atmoshere without oxidation. Duringthis erio both electric circuits areinterrupte and cool, dry hydrogen is permitted to pass over the tungstento aid in quickly reducing its temperature. When the temperature hasbeen finally reduced suiciently, the plug 20 is removed and the boat 25and its contents are withdrawn and refilled with tungsten trioxid for asecond o eration.

Although it is o vious that the process herein described may be carriedout by means of many different types of apparatus, the a paratus hereinillustrated is the most satis actory of any of which am at presentaware.

What I claim as new and wish to secure by Letters Patent of the UnitedStates is:

1. The method of reducing finely powdered metallic oxids which consistsin heating the oXid in an atmosphere of rapidly moving hydrogen whichhas been preheated to a temnerature equal to that ofthe metallic 0x1 g2. The method of reducing finely powdered tun sten trioxid whichconsists in passing a b ast of highly heated hydr en over the surface ofthe tungsten trioxi and at the same time heating the tungsten trioxidjust suliciently to overcome radiation, and to supply the necessary heatfor the va `ori`za tion of the moisture created by the re uction of theoxid.

In witness whereof, I hereunto subscribe myname this 8th day ofNovember, A. ll 1916.

CARL A. PFANSTI-EHL. Witnesses:

CLARENCE W. Bamm, MARGARET GRGBLEIN.

